Interferon -2b Decreases Hepatic Micrometastasis from Ocular Melanoma by Activation of NK Cells

Abstract

Abstract: : Purpose: To analyze the number of hepatic micrometastasis and NK activity in a murine model of ocular melanoma treated with interferon α-2b (INF). Methods: 5X10⁵cells/2.5µl aliquots of tissue culture B16LS9, B16F10 or Queens melanoma cells were inoculated into the posterior compartments (PCs) of the right eyes of 180 twelve-week-old female C57BL6 mice. The right eye was enucleated at 7 days post-inoculation and the mice were sacrificed at four weeks post-inoculation and the number of hepatic micrometastasis were counted. The mice were divided into control and treated groups for each cell line and two dosing schemes. The mice were treated with 20kIU INF IM 12 hours or qd for 4 days prior to enucleation. Control groups were given IM PBS. NK activity was assessed using a flow cytometric technique to determine %lysis of target melanoma cells. Results: Results showed a positive treatment effect with significantly fewer micrometastases in 4 day>1 day IFN treated mice in Queens>B16F10>B16LS9 cells. There was greater NK melanoma specific cytolysis in Queens>B16F10>B16LS9 cells. Conclusions: These results confirm the utility of IM IFN α-2b as a neoadjuvant therapy for controling eye melanoma hepatic micrometastasis and that the mechanism of this effect is increased NK anti-melanoma activity. This is a cell-line specific response.

Keywords: melanoma • animal model • pathology: experimental